Thermophysical characteristics of plaster composites reinforced with the addition of different wastes employed in green construction applications

The present work highlights the importance of using different local bio-waste-based materials as composite materials in the construction domain. In performed experiments, waste paper and vegetable fibers (luffa), extracted from the Meknassi region (Tunisia), were combined with a plaster matrix in order to improve the physical and thermal properties of the resulting composite. The obtained results show that paper and luffa waste have a high cellulose content and a high percentage of cellulose, which makes them highly-insulating and reinforcing materials in composite formulations. Several tests were carried out to examine the physical properties (density and water absorption) and thermal characteristics (Thermal diffusivity, specific heat capacity, Thermal conductivity and Thermal effusivity) of the developed composite materials. It was observed that gypsum manufactured using waste paper fibers provided a good balance between physical properties and thermal insulation and enhanced the thermal performance of the composite, especially its thermal conductivity-depending on the concentrations of waste paper and luffa fibers. The experimental findings also confirm that the incorporation of 10% (luffa fibers + waste paper) in the plaster produced a composite characterized by a conductivity of λ = 0.19 Wm−1.K−1, a diffusivity of α = 2.9 10−7m2/s and a density of ρ = 646.48 kg.m−3. Besides, it was observed that water absorption in composition C4 increased by 41%, compared to that of the pure plaster sample. Moreover, water absorption coefficient rose to 98%. It was also observed that reduced density made the produced material both lightweight and more insulating due to its low thermal conductivity. Based on the above-stated results, it may be deduced that the use of plaster reinforced with luffa fibers and waste paper is beneficial in the construction field. These composites can be used in form of plates employed to construct prefabricated walls, either for load-bearing structures or façade covering.